While old, this is an excellent resource (old does not mean bad in theology). A couple of specific features I would like to point out. The first one is:
The Theology Program https://bible.org/article/theology-program
If you don't know it's there you will probably not notice this. These are really good courses, went through them many, many years ago as part of the Calvary ABQ School of Ministry. If you click on the link above you will notice things in "blue," click on them (i.e. 258 theology questions and answers, Introduction to Theology, and so on). When you click on the topics you can actually download the course. There is reading and video (class discussion) for the classes. I think these are seminary level classes so I highly recommend.
The second thing in the NET Bible with notes (which is only online unfortunately) which is here:
“For indeed the day is coming, burning like a furnace, and all the arrogant evildoers will be chaff. The coming day will burn them up,” says the Lord who rules over all. “It will not leave even a root or branch. But for you who respect my name, the sun of vindication will rise with healing...
netbible.org
Blessings,
TheLayman